$0.74\times 0.422 = $
${0}$ ${7}$ ${4}$ ${0}$ ${4}$ ${2}$ ${2}$ ${\times\vphantom{0}}$ ${.}$ ${.}$ ${0.04}\times {0.002}= {0.00008}$ ${8}$ ${0.7}\times {0.002}= {0.0014}$ ${4}$ ${0}\times {0.002}+C{0.001}= {0.001}$ ${1}$ ${0.04}\times {0.02}= {0.0008}$ ${8}$ ${0}$ ${0.7}\times {0.02}= {0.014}$ ${4}$ ${0}\times {0.02}+C{0.01}= {0.01}$ ${1}$ ${0.04}\times {0.4}= {0.016}$ ${6}$ ${0}$ ${0}$ ${0.7}\times {0.4}+C{0.01}= {0.29}$ ${9}$ ${0}\times {0.4}+C{0.2}= {0.2}$ ${2}$ ${+\vphantom{0}}$ ${0}$ ${3}$ ${1}$ ${2}$ ${2}$ ${8}$ ${+\vphantom{0}}$ ${0}$ ${3}$ ${1}$ ${2}$ ${2}$ ${8}$ ${.}$ The top number has $2$ digits to the right of the decimal. The bottom number has $3$ digits to the right of the decimal. The product has $2+3=5$ digits to the right of the decimal. $0.74 \times 0.422 = 0.31228$